1. Field of the Invention
This invention relates to a photoresistive composition and also to a method of forming a pattern using such a composition. More particularly, the invent ion provides a new photosensitive composition and also a method of forming a pattern using such a photoresistive composition. The photoresistive composition and the pattern formation method according to the invention can be utilized for forming various patterns in the field of fabrication of electronic materials (such as semiconductor devices ).
2. Description of the Related Art
Up to date, there is a trend for finer and denser electronic materials, such as semiconductor devices. For example, the minimum width of semiconductor integrated circuit lines is now going from the order of sub-half micron to the order of quarter micron. To cope with this trend, the lithographic technology, in which the exposure light is short wavelength light of KrF eximer laser (248 nm), ArF eximer laser (193 nm), etc., is attracting attention. Heretofore, various types of photoresists have been proposed for use with such laser beams. For example, chemical amplification type photoresists are attracting attention. A typical chemical amplification photoresist, for instance of positive type, comprises a resin, a dissolution inhibition material and a photo acid generator (i.e., a photo-sensor). In the non-exposed area the dissolution inhibition material is not dissolved in aqueous alkaline solution (i.e., developer) for protecting the resin. But in the exposed area, acid is generated from the photo acid generator, and the dissolution inhibition material is released by this acid to become soluble in the aqueous alkaline solution. The acid acts as a catalyst and hence is not substantially consumed while progressively releasing the dissolution inhibition material. Thus, the photoresist is called chemical amplification type.
At present, however, the various photoresists such as those of the chemical amplification type are actually seldom utilized in various high resolution dry etching processes. (For recent techniques of this kind, see Nozaki et al, 1992 Autumn Proceedings of the Japan Society of Applied Physics, page 504, 17p-ZM-8, and Endo et al "Technical Digest of IEDM", 1992, page 46.)